To make the buttercream, beat the butter with an electric mixer until light and fluffy. Add the vanilla extract and mix to combine. Add the confectioner’s sugar one cup at a time, then beat for 3 minutes, or until light and fluffy.
Set aside about ¼ of the buttercream and add the matcha to the larger amount. Mix well.
Use a variety of piping tips to pipe different styles of trees onto the blondies. For the green and white effect, simply spread both colors of buttercream into the piping bag, then pipe away! The piping tip numbers that I used for each tree is featured on the screen of the video, to keep things simple.